1. Field of the Invention
The present invention relates to a lining material adapted for use in lining aging sewage pipes and other existing pipes and manholes, and a barrier liner that covers the external peripheral surface of the lining material, and a method for rehabilitating a pipe and a manhole using these materials.
2. Description of the Prior Art
Known in the art and practice is a lining method for lining existing pipes with a lining material in order to rehabilitate the existing pipes without excavation when sewage pipes and other existing pipes buried underground have aged (refer to Japanese Patent Application Laid-open No. 6-114939, for example). Lining material for rehabilitating an existing pipe (hereinafter also simply referred to as “pipe lining material”) is a material in which resin absorption material composed of a soft tubular nonwoven that corresponds to the shape of the existing pipe is impregnated with an uncured liquid curing resin (thermosetting resin, for example). A plastic film composed of a highly airtight polyethylene or the like is applied to cover the external peripheral surface of the resin absorption material. The purpose of the film is to waterproof the pipe lining material and to prevent the liquid curing resin from leaking through. During lining, the pipe lining material is turned inside out, inserted into an existing pipe by using fluid pressure, and pressed against the internal peripheral surface of the existing pipe. In such a state, the pipe is lined by thermosetting or using another method to cure the liquid curing resin impregnated in the pipe lining material. A plastic film on the pipe lining material becomes the internal peripheral surface side by the everted insertion process.
Prior to inserting the pipe lining material into an existing pipe, there are cases in which a soft tubular barrier liner for covering the external peripheral surface of the pipe lining material is inserted into the existing pipe as required in order to stop water from permeating from the periphery, to prevent the pipe lining material from being damaged, and to carry out other measures. The pipe lining material is then inserted inside the barrier liner to line the existing pipe. The barrier liner is composed of highly airtight polyethylene or another plastic film in the same manner as the plastic film of the pipe lining material.
There is also known and practiced a lining method for similarly lining an aging manhole in order to rehabilitate the manhole (refer to Japanese Patent Application Laid-open No. 8-150659, for example). The lining material for rehabilitating a manhole (hereinafter also simply referred to as “manhole lining material”) is the same as the pipe lining material, except that the shape corresponds to that of a manhole, and the manhole is lined using the material in the same manner as that used for lining existing pipes. However, the manhole lining material is ordinarily directly inserted without being turned inside out. Also, a plastic film is applied to only the external peripheral surface or to both the external and internal peripheral surfaces of the resin absorption material of the manhole lining material in accordance with differences or other aspects of the heating method for curing the thermosetting resin that is impregnated in the manhole lining material.
In conventional pipe lining and manhole lining materials, the durability (abrasion resistance, acid resistance, and the like) of plastic films such as polyethylene that are applied to the resin absorption material is inferior to that of resin absorption material impregnated with a curing resin (unsaturated polyester, vinyl ester, and the like). For this reason, if the lining work is ended and the existing pipe is again used without removing the plastic film after the lining material has been cured, the plastic film peels away and obstructs the flow of sewage water or the like in the pipeline.
It is for this reason that in a lining operation, work is performed to peel away the plastic film that has been applied to the internal peripheral surface of the resin absorption material of the lining material after the curing resin of the lining material has cured, and there is a drawback in that such work is laborious, project time is extended, and higher costs are incurred. There are also cases in which the entire plastic film cannot be cleanly removed and the internal peripheral surface of the lining material is damaged. In this case, the appearance is worsened, the roughness coefficient of the internal peripheral surface of the lining material is increased, and the flow rate within the existing pipe ends up being reduced. There is a further drawback in that costs are incurred to dispose of the plastic film that has been peeled away.
When a barrier liner composed of conventional polyethylene or another plastic film is used to line an existing pipe, an unneeded barrier liner is semi-permanently left behind after the lining work. For this reason, the barrier liner that has been left behind must eventually be disposed of when the existing pipe is excavated and removed as needed in the future, for example, and costs are thus incurred.
An object of the present invention is to solve the problems described above and to provide a lining material for rehabilitating an existing pipe and a manhole that allows piping and manhole lining work to be simplified and performed in a shorter period of time, and that can reduce operation costs and improve the lining finish, and to provide a barrier liner that can eliminate the need to ultimately dispose of the liner in the future after being used to line an existing pipe.